Trying to catch a cheating girlfriend, a thieving employee, the dog befouling your lawn or the kid who broke your priceless Ming vase? These expert private investigator tips will help you crack the ca

Anyone who’s seen the Sherlock Holmes films has likely daydreamed about being a clever detective. Catching people with their pants down, chasing bad guys through alleys, doing the work the cops can’t. For better or worse, says licensed P.I. Charles Clifton, the job is “80 percent mind-numbing boredom,” with the other 20 percent split between terror and laughing your ass off. Still, being able to privately investigate can come in handy if you’re trying to figure out whether your girlfriend is cheating—or which neighborhood pooch befouled your lawn. Try Clifton’s secrets and you just might make Robert Downey Jr. proud.

Editor’s note: We strongly advise that you check to see that whatever you’re going to do is legal in the city and state where you live.

Cheating girlfriend or wife

Deleted scene from Trapped in the Closet, anyone?

You may be surprised to hear that Clifton doesn’t do a whole lot of trying to catch folks in the act. “About 90 percent of PIs just starting out do, but I only really do that when it’s a missing persons or child custody case,” he says. Instead, first determine whether you have actual reasons to believe your partner is cheating. Are you just the hyper-jealous type? Before you go snooping around, make sure your suspicion is based on more than paranoia. Otherwise, you’ll just create problems out of nothing.

After you’ve decided to snoop? Start out by checking out her social media presence. The guy she’s cheating with is almost certainly on her Facebook friends list. Make a list of every alias and email address she uses online. Then do deep Google searches for each of them. (Go even deeper with the reverse email search site spokeo.com.) If any dating or social sites come up—like, say, Adult Friend Finder—discreetly join up and poke around. What you do with what you find, however, is entirely up to you.

Thieving employee

Yes, even cute employees have been known to steal company secrets.

The first thing you need to decide is, do you want to fire the employee or do you want to press charges? If you just want someone fired, all you have to do is set up a camera, but watch out: you can’t do that without the business owner’s permission. If you’re just managing the place, you’re going to have to check with the higher ups. This is also problematic because it requires reviewing hours of boring footage.

If you want to catch someone stealing cash, opt for unannounced drawer audits and forensic accounting. Getting someone to go undercover isn’t a bad idea, either, but you’d better pony up for a P.I. Explains Clifton: “Your brother is a less reliable source than a P.I., which the courts call a ‘disinterested third party.’ ”

Ever have a neighbor who didn’t much care where his pooch did its business? Don’t be the guy with the paintball gun laying in wait. It’s not the dog’s fault it has a crap owner (pun intended).

Instead, go to your favorite big box discount retailer and get some surveillance equipment. You can get court-quality footage and haul your neighbor to small claims court for the damage doggy has been doing to your lawn. Or you can just threaten him with it, and chances are he’ll curb his canine.

Lying kid

Another telltale sign of lying: the rare genetic condition known as Pinocchio-nose.

You come home from work to find your brand-new TV destroyed. Your kids—or nieces and nephews—taking a page from Family Circus, are all “Ida Know” and “Not Me.” Clifton recommends a technique called “shotgunning.” You’ve probably seen it in action before, either at the hands of a cop or your old man. It’s simply asking the same question, in slightly different ways, over and over in rapid succession.

Got two kids working together? Separate them and play one against the other. Any kernel of truth is helpful. If Kid A admits he and Kid B were playing football in the house, but he wasn’t near the TV, tell Kid B that Kid A ratted him out. It works on just about everyone but hardened criminals. We can only hope that term doesn’t apply to your offspring.